Or did you mean how long it takes until they get wiped? That'd be 6 months.
Usually the admins can't recover lost characters, therefore I don't get the point of your question.
Should be a pretty simple deal as all of the data was in their servers pre-beta(roll-back). That said I imagine they are pretty busy. I haven't seen anyone complain about NOT getting their recovery and I imagine there would be people doing so had that happened. Then again, I haven't looked for complaints much.
Processing that thing is a thorn in the side, and doing anything about it before rollback was without purpose. I'm about to yank that thorn out now. Sorry for the delay.